1. Field of the Invention
The present invention relates to a connection element for a bolt having an outer thread and including a member for receiving the bolt and having a bore through which the bolt extends, with the bore having a cylindrical receiving region and a tapering, at least sectionally, in a direction opposite to an insertion direction of the bolt, region that adjoins the cylindrical receiving region at its side facing in the direction opposite the insertion direction, and with the connector further including a locking member arranged in the bore and formlockingly engaging, at least partially, in the outer thread of the bolt for retaining the bolt in the bore, the locking member being formed as a radially expandable ring body an inner width of which is at least partially smaller than the outer diameter of the bolt and an axial length of which somewhat corresponds to a length of the cylindrical receiving region.
2. Description of the Prior Art
A threaded connection, which is one of the most used techniques of forming a connection, usually consists of two or more elements, generally, a threaded connection is formed by a bolt having an outer thread and a nut with a corresponding inner thread. A to-be-connected part can be connected with the bolt or the nut. Often, a bolt forms a component of the connectable part itself. The second connectable part, in this case is generally provided with a bore through which the bolt extends. The connection becomes fixed by screwing the nut on the bolt. Alternatively, a nut can constitute a component of a to-be-connected part. In this case, the bolt is screwed into the nut, extending through a bore of another to-be-connected part. The bolt can also be formed as a threaded rod connectable with a mounting for a pipe.
Known are connection in which for retaining a bolt, a connection element with an expandable ring body that engages in the outer thread of a bolt is used. The use of an expendable ring body provides for a simple and rapid connection. The drawback of the known connections consists in that they can transmit a very small torque. E.g., when a connection element is mounted on pipe shell to provide for connection with a threaded rod, it should be secured to a construction component with a dowel which is expanded by drilling. In this case, drilling of the pipe shell is not enough as the connection element does not transmit the torque adequately.
Accordingly, an object of the present invention is to provide a connection element with locking means engaging at least partially in the outer thread of a bolt and which insures an adequate transmission of a torque.
This and other objects of the present invention, which will become apparent hereinafter, are achieved by providing a connection element of a type described above in which the receiving member has a guide region that adjoins the cylindrical region at its insertion direction side and has an inner diameter which at most corresponds to an outer diameter of the bolt.
By providing, in the receiving member, a guide region having an inner diameter that does not exceed the outer diameter of the bolt, it is insured that the bolt is retained in the receiving member upon application of torque thereto. The guide region functions somewhat like a brake. As a result, the connection can be subjected to higher torques than the conventional connections.
Advantageously, the inner or root diameter of the guide region corresponds to the outer diameter of the bolt. In this case, there is provided a stop which adjoins the guide region at its insertion-direction side. The stop, which can be formed by a wall of the connection element, presents the extension of the bolt beyond the connection element.
Advantageously, the guide region has an inner thread arranged coaxially with the bolt receiving bore. Preferably, a frictional insert, which has a high friction coefficient, can be mounted in the guide region. Such an insert can be formed e.g., of plastic or elastometric material. When an insert is used, it is the insert that is provided with the thread. When a torque, which acts in a screw-in direction of the thread, is applied to the bolt, the bolt is subjected to high frictional forces which prevent the bolt from rotation.
Advantageously, the root diameter of the thread of the guide region is smaller than the outer diameter of the bolt, whereby a reliable force and/or frictional locking connection is provided between the receiving member and the bolt. In particular, a frictional insert substantially increases the friction between the connection member and the bolt. In addition, providing a guide region thread having a root diameter smaller than the outer diameter of the bolt insures an optimal wedging, e.g., of corners and edges of the receivable end of the bolt in the guide region. The wedging is particularly pronounced when so-called stock screws with a conical end are used.
In order to insure that the connection is usable to withstand sufficiently high torques, the inner thread of the guide region should have at least 1.5 turns. Advantageously, in order to insure a cost-effective production of the connection members, they are formed as one-piece members.
Advantageously, the guide region of the receiving member is formed by radially deforming inward a material of a wall of the receiving member at its insertion direction side by using a flanging process, and by, thereafter, axially expanding a deformed region with a die to form the guide region with a predetermined diameter.
The novel features of the present invention, which are considered as characteristic for the invention, are set forth in the appended claims. The invention itself, however, both as to is construction and its mode of operation, together with additional advantages of objects thereof, will be best understood from the following detailed description of preferred embodiment, when read with reference to the accompanying drawings.